TERRESTRIAL FAMILIES OF IIEMII'TERA-IIETEROPTERA 143 



ZnOGEOGRAPIlICAL NOTi:s ON THE HeTEROPTEROUS FaUNA OF HiGU ALTITUDES 



The zoogeographical pruljlems raised by the present collection center around the exist- 

 ence of a number of endemic species, some belonging even to endemic genera, at liigli 

 altitudes in a mountainous region which was undoubtedly subjected to intense glaciation 

 during the Quaternary Ice Age. 



Prior to the present investigation the highest recorded locality at which Heteropterous 

 bugs had been collected was Rongbuk in South Tibet, where at an altitude of 16,500 ft. 

 Kingston obtained much of his material of Chlamydatus pachycenis (Kiritshenko, 1931b). 

 A hitherto unrecorded nymph of Nysiits was also obtained by the same investigator at an 

 altitude of 17,000 ft. In the Yale North India Expedition collections the following four 

 species are represented from still greater elevations : 



Nysiiis cricar alticola siibsp. n., u\) to 5297 m. (17,381 ft.) 

 Dohnacoris dctcrrana gen. n., sp. n., up to 5300 m. ( 17,400 ft.) 

 Chlamydatus pachycenis Kiritsh., up to 5334 m. (17,500 ft.) 

 Tibctocoris margarcfae gen. n., sp. n., up to c. 5360 m. (17,600 ft. ) 



These four species fall into two ecological and zoogeographical groups. A^^. c. alticola 

 and C. pachycenis occur among grasses and small herbaceous plants, mostly Cruciferae, the 

 dominant members of the mesophj-tic high-altitude vegetation. Both are probably widely 

 distributed in the Himalayan and Karakorum ranges wherever the appropriate flora is devel- 

 oped, for, as has been pointed out, C. pachycenis and an undetermined species of Nysius 

 are known from but slightly lf)wer localities in the Everest region. It is also of interest to 

 note, that of the three free-living species of Heteroptera inhabiting Greenland, two (cf. 

 Qiina, 1934) belong to the genera Nysius and Chlamydatus. It is therefore very probable 

 that, during the Quaternary Glaciation, both these genera, and perhaps no others, could 

 survive in the highest zone of vegetation, in the immediate vicinity of the ice. D. deterraiia 

 and T. niari^arctae, on the other hand, are apparently confined to a drier type of hal)itat, 

 where the dominant plant is Artemisia minor Jacq. Both species belong to monotypic genera 

 most closely related to groups that reach their highest development in Central Asia. The 

 well-defined generic characters of Dolmacoris make it most improbable that it is a recent 

 immigrant to the western Tibetan Plateau and strongly suggests that the fauna of the present 

 region of xerophytic vegetation in this region has survived the Quaternary Glaciation in 

 unglaciated parts of Western Central Tibet under semi-arid conditions. 



The Pamirs are the only mountains of Central Asia of which the Heteropterous fauna 

 is at all well known. Here from heights of over 4,000 m. Kiritshenko (1931a) records 27 

 species of which three belong to the Acanthiidae, not treated in the present paper. Of the 

 24 truly terrestrial Heteroptera of the High Pamir only two are endemic species. Omitting 

 three forms only recorded from the Indus valley from localities lying below 4,000 m. and 

 in each case associated with poplar trees which do not grow above this height, the num])er of 

 species at present known from Indian Tibet is 11. If to these are added two extremely 

 doubtful records, a nymph of Psallus sp. (Dambu-guru) and Teratocoris sp. (Tukung, S. 

 of the Panggong Tso), which I noted but of which no specimens were found when the 

 collections were unpacked, the total number of species is increased to thirteen, just over half 

 the number recorded fnmi tlic High Pamir. Of these, however, si.x appear to be endemic 



